Background: Oral white lesions that cannot be clinically or pathologically characterized by any specific disease are referred to as leukoplakia. Such lesions are well known for their propensity for malignant transformation to the extent of 10-20%. Exfoliative cytology is a simple and useful screening tool for detection of malignant or dysplastic changes in such lesions.

Aims: A clinico-epidemiological and cytological study of oral leukoplakia was undertaken to detect their malignant potential and value of cytology in diagnosis.

Methods: This 2 year duration multicentre study was undertaken on all patients presenting with oral white lesions to the out patient department of the two institutions. Those cases in which a specific cause (infective, systemic disease or specific disease entity) for the white lesions were elicited were excluded from the study. The group with idiopathic white lesions was included in the study and was subjected to periodic exfoliative cytological study at three monthly intervals to detect any malignant change. Patients presenting less than two times for follow up were excluded from the final analysis of the study.

Results: Out of total 2920 patients studied, 89.53% showed benign, 9.93% showed dysplastic and, 0.72% showed malignant cells on exfoliative cytological study. All the dysplastic and malignant lesions were subjected to histopathological study by incisional biopsy. Among the dysplastic lesions 13.79% proved benign and the rest true dysplastic. Among the cytologically malignant group 4.76% showed dysplasia and the rest true malignant lesions.

Conclusion: Persistent leukoplakia has a potential for malignant transformation and exfoliative cytology could be a simple method for early detection of dysplastic and malignant changes.